A Question Of Health

Did air travel cause my knee problem? And should I worry about a swallowed penny?

Q. I went to hospital last week with a suspected deep vein thrombosis. My calf was swollen and painful, and I could barely straighten or bend my knee. It turned out not to be thrombosis, but a Baker's cyst of the knee. I was told that this may disappear without treatment. What is a Baker's cyst, and what causes it? Can one get one by sitting in an aeroplane seat for a long flight?

A. Baker's cysts are fluid-filled swellings that appear at the back of the knee. They are usually linked to an injury to the knee, such as a damaged cartilage, or to arthritis of the knee. But they can also occur in completely healthy and undamaged knee joints, and children can even have Baker's cysts. Occasionally, Baker's cysts burst or rupture, and the fluid spills out into the muscles of the calf. When this happens, the calf swells up and becomes painful. It sounds as though this is what happened to you last week. A ruptured Baker's cyst is often confused with a deep vein thrombosis (DVT) of the calf because the symptoms are virtually identical. But a DVT is potentially much more serious, because it can lead to blood clots travelling to other parts of the body, such as the lungs. The problems caused by a Baker's cyst always remain confined to the leg. DVTs are sometimes associated to long aeroplane flights (though this is controversial), but Baker's cysts are not linked to air travel.

CHOLESTEROL CONFUSION

Q. I am 52 and recently had my first cholesterol test. When I rang the surgery for my results, the receptionist said that they were: "3.3, well below the 5.5 safe maximum - and 5.5, well below the safe maximum of 7.4." I am confused as to why I was given two numbers, and the receptionist couldn't explain. What do they mean?

A. It's a sad state of affairs when a doctor does a blood test but can't be bothered to explain the result to the patient. I suspect that the first set of numbers refers to a type of cholesterol known as LDL cholesterol, and the second set refers to the total amount of cholesterol in your blood. I am puzzled by the actual information that you were given, but I will do my best to explain things. LDL cholesterol is the so-called "bad cholesterol". It accumulates in the wall of blood vessels and eventually leads to blocked arteries. HDL cholesterol (which hasn't been measured in your case) is known as "good cholesterol" because it is supposed to protect your arteries from getting clogged up. Total cholesterol is more or less the sum of the two, although the actual calculation of levels is slightly more complicated than simply adding the two together. Over the years, the recommended cholesterol levels for adults has come down. Ten years ago, we used to say that a total cholesterol level below 6.9 was "normal". These days, most experts now recommend a total cholesterol level of less than about 5. For LDL cholesterol, the current recommended level is less than about 3. If, as I suspect, your LDL level is 3.3 and your total cholesterol level is 5.5, you are doing pretty well. It is important, however, to remember that cholesterol levels are only one risk factor for heart disease. Not smoking, controlling your blood pressure, and taking regular exercise are at least as important as having a low cholesterol level. Consult www.bhf.org.uk, the website of the British Heart Foundation, to find out more about cholesterol and heart disease.

NO PENNY SPENT

Q. My two-year-old grandson has swallowed a penny. The NHS Direct helpline suggested that we wait and see. But so far, he has not passed the penny. Should we be worried?

A. UK pennies are made from copper-coated steel, and are 20.32mm in diameter. Neither copper nor steel will cause any serious problems if they are released into the body, so from the chemical point of view, your grandson will be fine. American pennies, however, are made mostly from zinc. When zinc is attacked by stomach acid, it forms a compound that can be very corrosive to the lining of the stomach. The only way that your grandson might come to any harm is if the penny gets stuck somewhere in his intestinal system. Every year, many thousands of small children swallow coins. Fortunately, it is extremely rare for the coins to get stuck. Usually, they simply pass through the intestines and eventually end up in the toilet. Look out for persistent abdominal pain or vomiting. If your grandson seems to be well, the penny will look after itself. If there is any suggestion that his intestine is becoming blocked, a simple X-ray will show where the penny is, and its progress can easily be followed with further X-rays.

Have your say: Readers write

MB from Kent had a bad experience with diuretics:

Shortly after I went on to diuretics to control hypertension, I experienced occasional periods of blurred vision lasting about 20 minutes. I realised this was caused by low blood potassium or, possibly, low magnesium. I now take chelated potassium tablets and magnesium tablets, and the problem has gone.

Send your questions and suggestions to A Question of Health, 'The Independent' 191 Marsh Wall, London E14 9RS; fax 020 - 7005 21 82; or e-mail health@independent.co.uk

Dr Kavalier regrets that he is unable to respond personally to questions